Add Sample Data

What does this MR do?

Relates gitlab-com/www-gitlab-com#7397 (closed)

MR adds in the first iteration of Sample Data, built on top of Project Templates, to allow for easier insertion into GitLab environments.

Screenshots

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.